lamba prob dead, causing stalling and rubbish idling...?

[CorradoVR6-Turbo 0]

The ECU controls the Idle valve mate,you defo have no air leaks?

 

Does it start up fine and idle from cold?

[-Neil- 0]

at the mo my ISV is disconnected, when i go to start my car up after it's been left over night i turn the key and it fires up and then stalls, so i have to apply slight gas peddal and rev it at 1k revs for a few seconds and then the idle will hover between 500-1k rpm.

 

Ive checked all the pipes i can think of for air leaks and i cant think of any that will be leaking, can you give me a list of which i should look out for.

 

I dont know if this makes a difference but i have noticed that in the top of the head under or in the inlet manifold where it goes over the enigine past the oil filler cap it has a kinda hollow air sucking sound??

 

Neil

[dr_mat 0]

The ISV controls the amount of air that bypasses the throttle (so that the engine can idle). It's supposed to close (almost) fully when you're accelerating and be opened instantly when you come off the throttle. With it disconnected, of course none of this works.

So. How is your throttle position sensor?

[CorradoVR6-Turbo 0]

I would spray brake cleaner or something like that (at your own risk) around the throttle body and inlet manifold,avoid the airbox inlet.

 

If the revs rise when you spary around them parts you have a air leak,strip and inspect.

 

As Mat said,check your TPS,do you have vagcom? you can see the tps reading in there and see how the percentage rises and falls with the throttle movment.

[-Neil- 0]

As Mat said,check your TPS,do you have vagcom? you can see the tps reading in there and see how the percentage rises and falls with the throttle movment.

 

Well on thursday i can get it VAGcom'd hopefull and see whats wrong with it! Going to strip all the intlet piping off 2morow and see if i can find anything that might be causing it to act funny!

 

This is really doing my head in now!

[CorradoVR6-Turbo 0]

OBD2...its the way not to stall!

[-Neil- 0]

Well ive just taken the whole inlet piping off and cleaned it all and checked everything, i also replaced this pipe..

 

 

the pipe goes to the CC, mine had melted on the mainfold heat shield, not sure if thats changed anything though.

 

also i reset the ECU (diconnected battery)

 

so i connected the ISV and went to start the car and...... it started first time, no problems, and idled fine, just been for a drive and it was trouble free.

 

But i do think that over the next few days of me driving it, it could back to its old problems (read that on here in a post somewhere)

 

Will have to wait and see.

[CorradoVR6-Turbo 0]

hope it stays that way mate,just have to wait and find out.

[-Neil- 0]

cheers CorradoVR6-n.o.s, you sugested the TPS, what signs would this show and are they expencive or hard to replace?

[CorradoVR6-Turbo 0]

not expensive to replace mate,easy to do. You should see a % in vag com,i cant remember off hand what the idle value should be? i think around 12deg on idle and then when you apply the throttle to full is should climb nice and stedy to 100deg.

[dr_mat 0]

Yeah the TPS value will go from "less than 15 degrees" to "more than 90 degrees". Typically about 12 or 13 to 92 or 93.

[-Neil- 0]

well had my car VAGCOM'd today, and there is no signal from the Lamba probe, ie, Its dead!

So got another one in order and it'll be fitted by garage next week, as well as some wheel bearings that need replace, oh and my front bumper is falling off, oh the joys of christmad!

 

So, would a dead lamba prob cause my car to idle crap and not run propperly?

And does it now run ok coz i've reset the ECU so the car has now learnt to run without it?

 

Thanks for your help guys!

[The_Dude 0]

it certainly won't have helped as the lambda monitors the air mixture in the exhaust gases to adjust the fuelling accordingly so if there is no signal it would have been on a default setting causing bad running due to incorrect stoichiometric values....i had mine replaced recently and it sorted a lot of problems.

[-Neil- 0]

it certainly won't have helped as the lambda monitors the air mixture in the exhaust gases to adjust the fuelling accordingly so if there is no signal it would have been on a default setting causing bad running due to incorrect stoichiometric values....i had mine replaced recently and it sorted a lot of problems.

 

brillaint, hopefully it'll sort alot of probelms out then, once its fitted i think the garage are going to reset the ecu or something with VAGCOM and monitor whats going on.

 

Also, i got another error:-

00793 Brake Pedal Position Sensor (G100)

 

I have noticed that sometimes at random occations, my ABS light comes on, either when driving, or braking, or just rolling in netrual.

 

What do i have to do to fix this fault?

[The_Dude 0]

it was a surprisingly coherent sentence, i'm amazed i pulled it off! :)